mbsrtowcs - convert a multibyte string to a wide-character string
#include <wchar.h> size_t mbsrtowcs(wchar_t *dest, const char **src, size_t len, mbstate_t *ps);
dest is not NULL, the mbsrtowcs()
function converts the multibyte string
*src to a wide-character
string starting at
dest. At most
len wide characters
are written to
dest. The shift state
*ps is updated.
The conversion is effectively performed by repeatedly calling
mbrtowc(dest, *src, n, ps) where
n is some positive
number, as long as this call succeeds, and then incrementing
dest by one and
*src by the number of bytes consumed.
The conversion can stop for three reasons:
An invalid multibyte sequence has been encountered. In this case,
*src is left pointing to the invalid multibyte sequence,
(size_t) -1 is returned, and
errno is set to
len non-L'\0' wide characters have been stored at
dest. In this case,
*src is left pointing to the next
multibyte sequence to be converted, and the number of wide characters
dest is returned.
The multibyte string has been completely converted, including the
terminating null wide character ('\0'), which has the side effect of
*ps to the initial state. In this case,
*src is set to NULL, and the number of wide characters written
dest, excluding the terminating null wide character, is
dest is NULL,
len is ignored, and the conversion
proceeds as above, except that the converted wide characters are not
written out to memory, and that no length limit exists.
In both of the above cases, if
ps is NULL, a static
anonymous state known only to the mbsrtowcs() function
is used instead.
The programmer must ensure that there is room for at least
len wide characters at
For an explanation of the terms used in this section, see attributes(7).
|mbsrtowcs()||Thread safety||MT-Unsafe race:mbsrtowcs/!ps|
POSIX.1-2001, POSIX.1-2008, C99.
The behavior of mbsrtowcs() depends on the LC_CTYPE category of the current locale.
Passing NULL as
ps is not multithread safe.
iconv(3), mbrtowc(3), mbsinit(3), mbsnrtowcs(3), mbstowcs(3)
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